Hitachi Relion 670 Series Applications Manual page 215

1MRK506375-UEN Rev. N
The phase angle difference level settings, PhaseDiffM and PhaseDiffA, shall also be chosen
depending on conditions in the network. The phase angle setting must be chosen to allow closing
under maximum load condition. A typical maximum value in heavy-loaded networks can be 45
degrees, whereas in most networks the maximum occurring angle is below 25 degrees. The
PhaseDiffM setting is a limitation to PhaseDiffA setting. Fluctuations occurring at high speed
autoreclosing limit PhaseDiffA setting.
tSCM and tSCA
The purpose of the timer delay settings, tSCM and tSCA, is to ensure that the synchrocheck
conditions remains constant and that the situation is not due to a temporary interference. Should the
conditions not persist for the specified time, the delay timer is reset and the procedure is restarted
when the conditions are fulfilled again. Circuit breaker closing is thus not permitted until the
synchrocheck situation has remained constant throughout the set delay setting time. Manual closing
is normally under more stable conditions and a longer operation time delay setting is needed, where
the tSCM setting is used. During auto-reclosing, a shorter operation time delay setting is preferable,
where the tSCA setting is used. A typical value for tSCM can be 1 second and a typical value for
tSCA can be 0.1 seconds.
Energizingcheck settings
AutoEnerg and ManEnerg
Two different settings can be used for automatic and manual closing of the circuit breaker. The
settings for each of them are:
• Off, the energizing function is disabled.
• DLLB, Dead Line Live Bus, the line voltage is below set value of ULowLineEnerg and the bus
voltage is above set value of UHighBusEnerg.
• DBLL, Dead Bus Live Line, the bus voltage is below set value of ULowBusEnerg and the line
voltage is above set value of UHighLineEnerg.
• Both, energizing can be done in both directions, DLLB or DBLL.
ManEnergDBDL
If the parameter is set to On, manual closing is also enabled when both line voltage and bus voltage
are below ULowLineEnerg and ULowBusEnerg respectively, and ManEnerg is set to DLLB, DBLL or
Both.
UHighBusEnerg and UHighLineEnerg
The voltage level settings must be chosen in relation to the bus or line network voltage. The
threshold voltages UHighBusEnerg and UHighLineEnerg have to be set lower than the value at
which the network is considered to be energized. A typical value can be 80% of the base voltages.
ULowBusEnerg and ULowLineEnerg
The threshold voltages ULowBusEnerg and ULowLineEnerg, have to be set to a value greater than
the value where the network is considered not to be energized. A typical value can be 40% of the
base voltages.
Because the setting ranges of the threshold voltages UHighBusEnerg/UHighLineEnerg and
ULowBusEnerg/ULowLineEnerg partly overlap each other, the setting conditions may be such that
the setting of the non-energized threshold value is higher than that of the energized threshold value.
The parameters must therefore be set carefully to avoid overlapping.
UMaxEnerg
Railway application RER670
Application manual
A disconnected line can have a considerable potential due to, for instance, induction from
a line running in parallel, or by being fed via the extinguishing capacitors in the circuit
breakers. This voltage can be as high as 30% or more of the base line voltage.
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Section 12
Control
209